Electronic display device for displaying calendar information

ABSTRACT

An electronic device having a calendar display function is capable of changing calendar formats to be presented on a display screen. The formats include a &#34;Sunday through Saturday&#34; mode and a &#34;Monday through Sunday&#34; mode. The device comprises a date counter which counts a date number from the first to the last days of a month. These date data are written into a display memory for the display screen and then are displayed on the display screen at appropriate locations which are different depending on which mode has been selected, in order to provide a desired calendar format.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic device for displayingcalendar information on a display unit thereof. More particularly, theinvention relates to an electronic device having a function to changecalendar formats to be displayed on the display unit.

2. Description of the Related Art

In recent years, electronic devices, such as electronic calculators,have had many functions. Among them is a calendar display function. Suchcalendar display function typically displays one-month calendarinformation in a matrix fashion in a fixed format of "Sunday throughSaturday". This format means that a week begins with Sunday.

The concept of what day is a first day of the week, however, isdifferent according to countries and peoples having different customsand cultures. In fact, in some cultures, Monday is a first day of theweek. Thus, the calendar format "Monday through Sunday" is used in manycountries. For users in these countries, electronic devices capable ofdisplaying only one calendar display format "Sunday through Saturday"are clearly undesired and inconvenient.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an electronic displaydevice capable of changing calendar formats to be displayed thereon byuser.

In accordance with the invention, there is provided an electronic devicewhich comprises:

display means, having a display screen, for displaying calendarinformation about at least one month, said display screen includingfirst and second display sections; input means for inputting "year" and"month" data; calculating means for calculating calendar informationbased on "year" and "month" data inputted from said input means;designating means for variably designating a calendar display formatdefining an arrangement of days of week; and control means forcontrolling said display means to display the calendar informationaccording to the display format designated by said designating means.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an electronic device according to anembodiment of the present invention;

FIG. 2 is a schematic representation of a memory for calendarinformation;

FIGS. 3A and 3B are views of displayed calendars in "Sunday throughSaturday" and "Monday through Sunday" modes, respectively; and

FIG. 4 is a flow chart of an operation of the illustrated embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is shown an electronic display devicehaving a calendar display function. The electronic device compriseskeyboard 1 coupled to control unit 2. Keyboard 1 includes a "S/M" key 1afor designating or selecting a (monthly) calendar display mode fromeither "Sunday through Saturday" or "Monday through Sunday" mode, and"calendar" key 1b for causing displaying of the calendar. Keyboard 1further includes other function keys and numerical keys, not shown inthis figure.

Key input data from keyboard 1 is supplied to control unit 2. Controlunit 2 includes read only memory (ROM) storing programs for controllingall circuits in the electronic device. Upon receiving "S/M" key inputdata from keyboard 1, control unit 2 writes or updates mode memory 3with flag data indicative of the calendar display mode designated by the"S/M" key. Flag data "1" represents "Sunday through Saturday" mode,while flag data "0" represents "Monday through Sunday" mode. The flag istoggled by successive "S/M" key operations.

"Year" and "month" data are entered from keyboard 1 and transferred toA-register 51 in data memory 5 through control unit 2. Calendar datacalculating unit 4 determines, based on the data of A-register 51, "dayof the week" of the first day of the month associated with the "year"and "month" data stored in A-register 51 and "data of the month" of thelast day of the same month. A method of this calculation is described indetail in U.S. Pat. No. 4,205,516, the entire contents of which areincorporated herein by reference. According to this calculation, Sundayto Saturday are represented by successive number "0" to "6"respectively.

First day data indicative of "day of the week", obtained by thecalculation of the calendar data calculating unit 4, is stored inB-register 52, and the last day data indicative of "date of the month"is stored in C-register 53.

Date counter 6 is reset and incremented by control unit 2, when acalendar display function is performed. The count of the date counter 6is supplied to comparator 9 for comparison with the last date data inC-register 53 in data memory 5. The comparison result of the comparator9 is inputted to control unit 2 which uses it to terminate the task ofcalendar display.

Display memory 8 stores date data for display areas of display unit 10.Memory control unit 7 includes pointer 71 which locates an area ofdisplay memory 8 where date data from the date counter 6 is stored.Correspondence between areas in display memory 8 and values of pointer71 are shown in FIG. 2.

Display unit 10 comprises first or day display area 101 for displayingdays of the week, and second or date display area 102 for displayingcalendar dates of one month, as shown in FIG. 3A or FIG. 3B. Thesedisplay areas preferably comprise a matrix type liquid crystal displayunit. The first display area 101 is divided into seven day displayblocks, and the second display area 102 has thirty-seven display blockstherein. Dates (numeral) and days of the week (characters) are indicatedby dot matrix patterns. The "days of week" data, which is week patterndata to be displayed on the first display area 101, is supplied fromweek-format ROM 11 which stores two different week-format data, "SU MO .. . SA" and "MO TU . . . SU". One of them is selected by the flag stateof mode memory 3.

Operation of the above-described device will be described below withreference to FIGS. 1 to 4.

When calendar display function is performed, its mode is previously setto either "Sunday through Saturday" mode or "Monday through Sunday" modeaccording to "S/M" key operation. Then "year" and "month" data isinputted and "calendar" key 1b is depressed. The inputted "year" and"month" data is stored into A-register 51 and a calendar displayingprocess represented by the flow chart or FIG. 4 is performed.

It is assumed here that "1989" as year data and "1 (January)" as monthdata are inputted from keyboard 1.

At first, calendar data calculating unit 4 determines "day of the week"of the first day of the month and "last date" of the month in step Al.This results in day data of "0 (Sunday)" for the first day of the monthof January (1989) and date data of "31" for the last day of the month.The first day data "0" is entered into B-register 52, and the last datedata "31" is entered into C-register 53. Then the pointer 71 is set tothe first day data in step A2. In this case, the pointer 71 is set to"0".

Next, in step A3, the display mode is checked. If the "Sunday throughSaturday" mode has been set by mode memory 3, the process is advanced tostep A4. In step A4, the pattern of SU MO TU . . . SA" is read out fromweek-format ROM 11 and entered into the display memory 8 at locationscorresponding to the day display area 101 of the display unit 10.

In step A5, control unit 2 sends a signal to reset the date counter 6 to"1" indicative of the first date. In step A6, this count "1" is writteninto the display memory 8 at a location pointed by the pointer 71, here,having a value of "0". In the next step A7, the comparator 9 comparesthe count of the date counter 6 with the last date data of "31" inC-register 53. The comparison results in a mismatch here, so thatprocess goes to step A8 in which date counter 6 and pointer 71 areincremented by one. At the next step A6, the incremented value "2" ofthe date counter 6 is written into the display memory 8 at a second datelocation specified by the pointer 71 having a value of "1".

The loop of the steps A6, A7 and A8 is repeated until the incrementedvalue of date counter 6 reaches the last date value of C-register 53.Thus, the successive counts "3,4, . . . " of date counter 6 are writteninto the display memory 8 at locations pointed by pointer 71 value of"2,3, . . . ", respectively. When the last date value "31", of datecounter 6 is written into the display memory 8 at a location addressedby the pointer 71 value "30" at step A6, the process is advanced to thenext step A9 through step A7 to display the calendar of "1989, January"on the display unit 10 as shown in FIG. 3A.

If "Monday through Sunday" mode is found in step A3, the process movesthe step A10 in which the pattern of MO TU WE . . . SU" is read out fromweek-format ROM 11 and written into display memory 8. This week-formatdata is displayed on the first display area 101 of the display unit 10.The next step All checks to see whether or not "day of the week" of thefirst day of the month is Sunday. Since "1989. 1. January" is Sunday asdescribed above, this is the case where the process goes to step A12. Instep A12, the pointer 71 is set to "7". And then the value of pointer 71is decremented by one at step A13. This descrementing process meanschanging the calendar display format from "Sunday through Saturday" modeto "Monday through Sunday" mode. The step A12, which changes the pointer71 to "7" from "0" previously set in step A2, is to avoid an invaliedcalculation "0-1" in step A13 when the first day of the month is Sunday.

In step A5 after step A13, the date counter 6 is initialized to "1". Inthe next step A6, this "1" is entered into the display memory areadesignated by pointer 71, which value is now "6" and is shown to pointto the memory location of "6"in FIG. 2. The process represented by stepsA6-A8 is the same as described before. The final step A8 controls thedisplay unit 10 to indicate the month calendar of "1989, January" in theMonday through Sunday"mode as shown in FIG. 3B.

If "day of the week" the first day of the month is not Sunday, the checkin step All yields NO. In this case, the process directly moves fromstep All to step A13 in which the "day of week" value of the first dayof the month is decremented by one. The process after step A13 is thesame as mentioned before.

As seen from above, the calendar display format is easily changed by akey operation between "Sunday through Saturday" and "Monday throughSunday" modes. This will help users make their own time schedules andproceed with their work accordingly.

Various modifications and alternations of the illustrative embodimentwill be obvious to a person skilled in the art without departing fromthe scope of the invention as defined by the appended claims. Forexample, other calendar display modes may be provided in which a week isshown to start with a day other than Sunday or Monday.

What is claimed is:
 1. An electronic device comprising:display means,having a display screen, for displaying calendar information about atleast one month, said display screen including a first display sectionarranged to display days-of-week information and a second displaysection, arranged to display date information about a month, having aplurality of display lines, each line having seven display areas; inputmeans for inputting "year" and "month" data; calculating means forcalculating calendar information base on "year" and "month" datainputted from said input means; designating means for variablydesignating a calendar display format defining an arrangement of days ofthe week; and control means for controlling said display means todisplay the calendar information according to the display formatdesignated by said designating means, including means for displaying thedays-of-week information on said first display section and means forentering date information into said display areas of said second displaysection in a manner corresponding to the displayed day-of-weekinformation.
 2. An electronic device according to claim 1,comprising:memory means for storing a plurality of different displaypatterns each representing days-of-week to be displayed on said firstdisplay section; wherein said control means further includes: selectingmeans responsive to said designating means for selecting one of saiddisplay patterns from said memory means to be displayed on said firstdisplay section.
 3. An electronic device according to claim 2, whereinsaid memory means includes means for storing at least a "Sunday throughSaturday" display pattern and a "Monday through Sunday" display pattern.4. An electronic device according to claim 1, wherein said means forentering date data includes:counting means for counting numbers from anumber "1", and moving means for moving the numbers of said countingmeans into said display areas.
 5. An electronic device according toclaim 4, wherein said calculating means includes means for obtaining "aday of the week" of a first day of a month.
 6. An electronic deviceaccording to claim 5, wherein said moving means includes means forstarting entering data from a display area of a first line correspondingto the day of the week obtained by said means for obtaining.
 7. Anelectronic device according to claim 6, wherein said calculating meansincludes means for determining the last date data of the month, and saidcounter means is incremented by one until its count reaches the lastdate data.
 8. An electronic device according to claim 4, wherein saiddisplay areas of said second display section are numbered by 0 to 36,with "0" corresponding to a first area of a first line and with "36"corresponding to a second area of a sixth line, and said moving meansincludes pointer means for successively pointing to difference ones ofsaid display areas.
 9. An electronic device according to claim 8,wherein said moving means includes:first means selectively responsive tosaid designating means for initializing said pointer means to a firstday value from said means for calculating, indicative of "a day of theweek" of a first day of a month when a "Sunday through Saturday" modehas been designated; and second means selectively responsive to saiddesignating means for initializing said pointer means to a valuedecreased by one from said first day value from said means forcalculating when a "Monday through Sunday" mode has been designated. 10.An electronic device according to claim 9, wherein said counting meansis incremented by one, and its incremented count is entered into saidsecond display section at a display area pointed to by said pointermeans each time when said pointer means is incremented by one.
 11. Anelectronic device according to claim 2, wherein said designating meansincludes:key input means for directing a change in a calendar displayformat between a "Sunday through Saturday" mode and a "Monday throughSunday" mode.
 12. An electronic device according to claim 11, whereinsaid control means includes:memory means for storing a "Sunday throughSaturday" display pattern and a "Monday through Sunday" display pattern;and counting means for counting numbers from a number "1"; said meansfor displaying the days-of-week information includes means for selectingone of the display patterns from said memory means, and said means forentering date data includes means for entering the number counted bysaid counting means into said display areas of said second displaysection in order.
 13. An electronic device according to claim 12,wherein said calculating means includes means for obtaining "a day ofthe week" of a first day of a month and the last date data of the month,and said means for entering the counted number includes means forentering data beginning from a display area corresponding to the firstday of the month.